1. Field of the Invention
The present invention relates to a device for grinding a liquid crystal display panel, and, more particularly, a device that grinds edges of a unit liquid crystal display panel after liquid crystal display panels fabricated on a pair of wide mother substrates are cut into individual unit liquid crystal display panels.
2. Background of the Related Art
Generally, in a liquid crystal display device, data signals are supplied to liquid crystal cells arranged in a matrix according to image information to display a demanded image by controlling a light-transmittance of each of the liquid crystal cells.
The process of cutting a large mother substrate into unit liquid crystal display panels generally includes a process of forming a scribing line on a substrate of a mother substrate using a pen having a hardness greater than that of glass and a process of propagating a crack along the scribing line. Such a cutting process of the unit panels is explained in detail by referring to the attached drawings.
FIG. 1 illustrates a cross-sectional view of a first mother substrate having thin film transistor array substrates and a second mother substrate having color filter substrates, in which the first and second mother substrates are bonded to each other to construct a plurality of liquid crystal display panels.
Referring to FIG. 1, in unit liquid crystal display panels, each of thin film transistor array substrates 1 has one side protruding longer than that of each of corresponding color filter substrates 2. This is because gate and data pad parts(not shown in the drawing) are formed at the corresponding edges of the thin film transistor array substrate 1 that are not overlapped by the color filter substrate 2.
Hence, the color filter substrates 2 on the second mother substrate 30 are separated from each other by a dummy area 31 that corresponds to the area of each of the thin film transistor array substrates 1 on the first mother substrate 20 that does not overlap the color filter substrate 2.
Moreover, the unit liquid crystal display panels are arranged properly to make best use of the first and second mother substrates 20 and 30. Depending on the models being fabricated, the unit liquid crystal display panels are generally formed to be separated from each other by an area of another dummy area 32.
After the first mother substrate having the thin film transistor array substrates 1 has been bonded to the second mother substrate 30 having the color filter substrates 2, the liquid crystal display panels are individually cut. In this case, the dummy area 31 of each of the color filter substrates 2 of the second mother substrate 30 and the other dummy area 32 separating the unit liquid crystal display panels from each other are removed simultaneously.
FIG. 2 illustrates a schematic layout of an individually cut unit liquid crystal display panel according to a related art.
Referring to FIG. 2, a unit liquid crystal display panel 10 includes an image display part 13 having liquid crystal cells arranged in a matrix form, a gate pad part 14 connecting gate lines GLN˜GLm of the image display part 13 to a gate driver integrated circuit(not shown in the drawing) for supplying gate signals, and a data pad part 15 connecting data lines DL1˜DLn of the image display part 13 to a data driver integrated circuit(not shown in the drawing) for supplying image information. In this case, the gate and data pad parts 14 and 15 are formed on edge areas of a thin film transistor array substrate 1 having long sides and short sides protruding longer than those of a color filter substrate 2.
In this case, the data and gate lines DL1˜DLn and GL1˜GLm cross each other on the thin film transistor array substrate 1. Thin film transistors (TFTs) are formed at the crossings of the gate and data lines to switch respective liquid crystal cells. Pixel electrodes are connected to the thin film transistors to apply electric fields to the corresponding liquid crystal cells, and a passivation layer is formed on an entire surface to protect the data lines DL1˜DLn, gate lines GL1˜GLm, thin film transistors, and electrodes.
Color filters are formed on the color filter substrate 2 and are separated from adjacent cells by a black matrix. A common electrode is also formed on the color filter substrate 2 as a counter electrode of the pixel electrodes on the thin film transistor array substrate 1.
A cell gap is provided between thin film transistor array and color filter substrates 1 and 2, which face each other, to leave a predetermined interval between them. The thin film transistor array and color filter substrates 1 and 2 are bonded to each other by a sealing part (not shown in the drawing) formed on a periphery of the image display part 13. A liquid crystal layer (not shown in the drawing) is formed in the cell gap.
Meanwhile, a short-circuiting line number (not shown in the drawing) is formed on an edge of the thin film transistor array substrate 1 in order to prevent static electricity generated by the patterned conductive layers on the thin film transistor array substrate 1.
The short-circuiting line should be removed after the liquid crystal display panels are cut into individual unit liquid crystal display panels.
Hence, after the liquid crystal display panels have been cut into individual unit liquid crystal display panels, edges of the unit liquid crystal display panel are ground to remove the short-circuiting line. Moreover, the edges of the unit liquid crystal display panel are ground to prevent the edges from being torn apart by an external impact as well as the danger of hurting an operator with the sharp edges of the unit liquid crystal display panel.
A process of grinding the above-explained unit liquid crystal display panel is explained in detail by referring to the attached drawing as follows.
FIG. 3 illustrates a block diagram of a device for grinding a liquid crystal display panel according to a related art.
Referring to FIG. 3, a device for grinding a liquid crystal display panel according to a related art includes a loading unit 50 for loading a unit liquid crystal display panel 10, a first grinding unit 53 for receiving the unit liquid crystal display panel 10 loaded by the loading unit 50 on a first grinding table 51 and for grinding short sides of the unit liquid crystal display panel 10 through a first grinding wheel 52, a turning unit 54 for turning the unit liquid crystal display panel 10 by 90° after its short sides have been ground, a second grinding unit 57 for receiving the turned unit liquid crystal display panel 10 on a second grinding table 55 and for grinding long sides of the unit liquid crystal display panel 10 through a second grinding wheel 56, an unloading unit 58 for receiving to unload the unit liquid crystal display panel 10 after its long sides have been ground.
Thus, in order to grind the edges of the unit liquid crystal display panel 10 in the device for grinding the liquid crystal display panel according to the related art, the first grinding unit 53 grinds the short sides of the unit liquid crystal display panel 10; then, the turning unit 54 turns the unit liquid crystal display panel 10 having the grinded short sides by 90°, and the second grinding unit 57 grinds the long sides of the unit liquid crystal display panel 10.
As mentioned in the foregoing explanation, in order to grind the edges of the unit liquid crystal display panel, the device for grinding the liquid crystal display panel according to the related art has the first grinding unit grind the short sides of the unit liquid crystal display panel and has the second grinding unit grind the long sides of the unit liquid crystal display panel. If the first or second grinding unit is broken or malfunctions, the related art grinding device cannot grind all edges of the unit liquid crystal display panel until it is fixed. Hence, the device for grinding the liquid crystal display panel according to the related art has a reduced efficiency thereby decreasing productivity.